We run an Apache Mod_proxy cluster with 3 JBoss in three dedicated server. Because we need share many files (small object files which our apps need to read/write ) between these JBoss servers ,we using NFS in Apache node and mount them into each JBoss Node as same directory.
Both nodes are installed RHEL 5.4 version and there are in same intranet network. We have 8G RAM in each server.
The problem is we got linux cache increased about 2-3M per minute, in heavy load day (about 100-150 online user ) the server cache will increased to about 3-4G each day.
After run these clean code:
sync
echo 3 > /proc/sys/vm/drop_caches
It will back to normal level:
total used free shared buffers cached
Mem: 8173504 589772 7583732 0 87444 72100
-/+ buffers/cache: 430228 7743276
Swap: 5799928 0 5799928
We want to know are these caused by JBoss open files not closed?
Are they other solutions we can use to share files between servers?
Thanks for any reply.
Best Answer
Linux will normally use all available memory. The memory that is not being used by application data will then be used by buffers and caches to speed access to disks and hardware. What you are describing seems like normal behavior. The caches will get smaller to allow application data to grow if needed, unless you change the
swapiness
vm parameter for the kernel. Swapiness is:You can read more about it here. Normally the default is ok, and if you are not having any process being killed by lack of memory the caches are nothing to worry about.